JSUMO QTR-8RC Line Sensor (RC Time Digital)

The QTR-8RC Reflectance Sensor Array is a high-performance line detection module developed for robotics and automated navigation systems. The module incorporates eight infrared LED and phototransistor pairs mounted at a spacing of 0.375 inches (9.525 mm) , providing excellent coverage for tracking lines and detecting surface reflectivity. Unlike traditional analog line sensors, the QTR-8RC uses an RC timing measurement technique . To obtain a reading, the microcontroller first charges the sensor output line and then measures the discharge time through the integrated phototransistor. The discharge rate depends on the amount of reflected infrared light received by the sensor. A highly reflective surface produces a shorter discharge time, while darker surfaces result in longer discharge times. This method provides increased sensitivity and allows direct measurement using digital I/O pins without requiring an ADC. Each sensor output is independent, enabling simultaneous reading of all eight channels. The infrared LEDs are arranged in pairs to reduce current consumption, while an integrated MOSFET allows complete control over LED operation. This feature supports power-saving modes and advanced sensing techniques such as PWM-controlled brightness adjustment. The sensor is intended to be mounted parallel to the surface being measured and is widely used in line-following robots, autonomous navigation systems, and reflectance-based detection applications. Specifications Parameter Specification Model QTR-8RC Sensor Type Reflectance Sensor Array Technology Infrared Reflection Number of Sensors 8 Channels Sensor Elements IR LED + Phototransistor Pairs Sensor Pitch 0.375 in (9.525 mm) Output Type RC Time Digital Output Reading Method Charge and Discharge Timing ADC Required No LED Control MOSFET Controlled Power Saving Feature Yes Channel Outputs Independent Outputs Mounting Orientation Parallel to Surface Application Type Line Tracking and Reflectance Detection Applications Line Follower Robots Autonomous Mobile Robots Maze Solving Robots Robot Navigation Systems Industrial Automation Systems Reflectance Measurement Applications Surface Detection Systems Educational Robotics Projects Research and Development Platforms Competition Robotics Path Tracking Systems General Proximity Sensing Applications